i have a 93 f150 v8 351 2x4, i went to start my truck and noticed my "battery volt gauge went to 0, then right after the oil pressure gauge went to under normal" so im like whats going on, then as im driving it back home to the garage my car had NO power in drive(auto tranny) and also made a loud clunking sound in the lower rpm range, so i put it in second and first gears and it seemed to drive fine, fluid levels for oil and tranny are normal. and no leaks under the truck. tested alternator and its fine. SO whats the problem? tranny? electrical problem? vaccum? im not sure whats going on but im sure this is a mystery case.